• I know nothing, but this doesn't seem right - Dibble 04:45:38 12/22/04 (2)
  In Reply to: Ella p-2-p posted by bcherry on December 16, 2004 at 03:44:39:

  It seems odd that the wiring for the two small tubes at the top (the 6922s?) isn't the same for both channels. The power goes to pins 4 and 5 on both (if I'm counting them correctly) and there are other similarities, but for example the NFB goes to pin 8 on one side and 3 on the other. Surely the wiring should be identical on both sides, just like it is for the other tubes?
  
  

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  • Dual triode - duh! - Dibble 19:38:09 12/22/04 (1)
    In Reply to: I know nothing, but this doesn't seem right posted by Dibble on December 22, 2004 at 04:45:38:

    OK, I get it. The 6922 is a _dual_ triode so Plate/Grid/Cathode are pins 1/2/3 (unit 2) and 6/7/8 (unit 1) and it's just that triodes 1 and 2 are swapped over on each side.

    Is there any reason for doing this? Wouldn't it still be better to have it symmetrical?
    
    
    

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    • Re: Dual triode - duh! - bcherry 22:00:26 12/23/04 (0)
      In Reply to: Dual triode - duh! posted by Dibble on December 22, 2004 at 19:38:09:

      OK, (casting about for a plausible explanantion): Because later you can swap tubes and give each half of the triode the same duty cycle.
      ;o)

      Brian
      
      Take control! DIY.
      
      

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• Re: Ella p-2-p - Victor_A 21:00:41 12/17/04 (2)
  In Reply to: Ella p-2-p posted by bcherry on December 16, 2004 at 03:44:39:

  Brian, thank you for the picture, it is really helpful.

  Please note -- Connection missing --Left Channel-- Tube 2-- Pin 5 to 47K resistor.
  Wrong connection -- Right Channel Tube 2 -- 1 MOhm resistor connected to pin 8, but have to be connected to the pin 1.

  Notice for those, who already have assembled ELLA and will redo it P-to-P --Power tubes (marked A,B,C,D in manual)-- Tubes A&C "default" (according to the manual) connected to P2G2, Tube B&D connected to P1G1.
  So, if you would not like to reassemble the output stage, you have to change wires, coming from 0.01 uF capacitors through 1 KOhm resistors to pins 5 of power tubes.

  Further, Input tube on the left channel have "changed" pins -- input is pin 2, (the "second tube"), not the pin 7 ("first tube" -- as in the right channel).

  Regards,

  Victor Androsenko
  
  

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  • Ella p-2-p corrected and enhanced - bcherry 01:39:23 12/20/04 (0)
    In Reply to: Re: Ella p-2-p posted by Victor_A on December 17, 2004 at 21:00:41:

    See the original picture
    Brian
    
    Take control! DIY.
    
    

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  • Re: Ella p-2-p - bcherry 22:57:41 12/17/04 (0)
    In Reply to: Re: Ella p-2-p posted by Victor_A on December 17, 2004 at 21:00:41:

    Thanks Victor,
    Appreciate the scrutiny and will review corrections Monday when Benny gets back.
    Brian
    
    Take control! DIY.
    
    

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• Re: Ella p-2-p - Olaf Zenker 02:46:08 12/17/04 (1)
  In Reply to: Ella p-2-p posted by bcherry on December 16, 2004 at 03:44:39:

  Hello,

  that capacitor and resistor between the plus and minus output for the speakers; is this to secure the amp in case off running without output-resistance?

  And, is this layout an example with or without feedback?

  Thanks for the informations

  Olaf
  
  
  

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  • Re: Ella p-2-p - zarniwoop 16:53:51 12/17/04 (0)
    In Reply to: Re: Ella p-2-p posted by Olaf Zenker on December 17, 2004 at 02:46:08:

    that RC on the speaker outputs is a zobel network... maybe intended to damp some ringing in the OPT. You'd have to ask the designer, or rig up a test setup and see whats going on. I think its unnecessary when using output triodes because of their low rp, but thats just my guess.

    This layout has feedback (looks like a 30K and paralled cap.)... 24k was stock , IIRC.

    -zarni

    
    
    

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• Re: Ella p-2-p - Brian D 22:29:02 12/16/04 (1)
  In Reply to: Ella p-2-p posted by bcherry on December 16, 2004 at 03:44:39:

  Looks very clear, even for someone like me.

  Brian, are you selling all of the parts as a package that will be needed to do this?

  Tks

  BrianD
  
  

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  • Re: Ella p-2-p - bcherry 22:59:23 12/17/04 (0)
    In Reply to: Re: Ella p-2-p posted by Brian D on December 16, 2004 at 22:29:02:

    Hi Brian,
    Yes working on it. stay tuned!
    Brian
    
    Take control! DIY.
    
    

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